Method and device for cooling rolls

Abstract

The invention relates to a method for cooling a roll ( 1 ), in particular a working roll ( 1 ) of a hot-rolling system, comprising the steps of feeding coolant ( 3 ) by means of a nozzle ( 5 ) into a gap ( 7 ) between at least a portion of the roll surface and a cooling shell ( 9, 11 ) that can be placed against the portion of the roll surface, and adjusting the gap height (h) between the cooling shell ( 9, 11 ) and the roll surface. According to the invention, the adjustment of the gap height (h) comprises either measuring the pressure (p act ) of the fed coolant ( 3 ) or measuring the volumetric flow rate (V act ) of the fed coolant ( 3 ). The invention further relates to a corresponding device ( 10 ) for cooling a roll ( 1 ).

The invention claimed is: 
     
       1. Method of cooling a roll ( 1 ) of a hot rolling installation, comprising the steps of:
 feeding of a coolant ( 3 ) with a nozzle ( 5 ) in a gap ( 7 ) between at least a portion of a roll surface and a cooling shell ( 9 ,  11 ) mountable on the portion of the roll surface; 
 setting a gap height (h) between the cooling shell ( 9 ,  11 ) and the roll surface; and 
 carrying out one of the following steps: 
 measuring a pressure (p act ) of the fed coolant and setting the gap height (h) on basis of the measured pressure (p act ); and 
 measuring a volume flow rate (V act ) of the fed coolant ( 3 ) and setting the gap height (h) on basis of the measured volume flow rate (V act ). 
 
     
     
       2. The method according to  claim 1 , wherein the pressure measuring and volume flow measuring steps include, respectively, increase of the gap height (h) between the roll ( 1 ) and the cooling shell ( 9 ,  11 ) when the measured coolant pressure (p act ) and the measured volume flow rate (V act ) lies, respectively, above a predetermined upper threshold of the gap height (h), and reducing the gap height between the roll ( 1 ) and the cooling shell ( 9 ,  11 ) when the measured coolant pressure (p act ) and the measured volume flow rate (V act ) lies respectively below a predetermined lower threshold of the gap height. 
     
     
       3. The method according to  claim 1 , comprising the steps of:
 in case of measuring the pressure, 
 feeding the coolant ( 3 ) into the gap ( 7 ) with a predetermined flow volume rate (Vx) and carrying out the setting of the gap height (h) between the roll and the cooling shell in accordance with the measured coolant pressure (p act ) based on a preliminary obtained pressure-distance characteristic (Kx) for the predetermined volume flow rate (Vx) of the coolant; and 
 in case of measuring the volume flow rate, 
 feeding the coolant ( 3 ) into the gap ( 7 ) with a predetermined pressure (p x ) and carrying out the setting of the gap height (h) between the roll ( 1 ) and the cooling shell ( 9 ,  11 ) in accordance with the measured volume flow rate (V act ) based on a preliminary obtained volume flow rate-distance characteristic (K x ) for the predetermined pressure (p x ) of the coolant. 
 
     
     
       4. The method according to  claim 3 , comprising the steps of:
 in case of measuring the pressure 
 comparing the measured coolant pressure (p act ), based on the pressure-distance characteristic (K x ), with a predetermined set height (h set ) of the gap ( 7 ); and in 
 accordance with amount of deviation produced by this comparison, generating adjustment value (S adj ) for setting the gap height (h); and 
 in case of measuring the volume flow rate, 
 comparing the measured volume flow rate (V act ), based on the volume flow rate-distance characteristic (K x ), with a predetermined set height (h set ) of the gap ( 7 ); and 
 in accordance with the amount of the deviation produced by this comparison, generating an adjustment value (S adj ) for setting the gap height (h). 
 
     
     
       5. The method according to  claim 3 , comprising the step of obtaining the pressure-distance and volume flow rate-distance characteristics (K x ) by a numerical simulation or experimentally. 
     
     
       6. The method according to  claim 4 , comprising the steps of:
 in case of the predetermined volume flow rate, producing the pressure-distance characteristic (K x ), for at least one volume flow rate (V x ) of the coolant ( 3 ) used for cooling the roll ( 1 ); and 
 in case of the predetermined pressure, producing the volume flow rate-distance characteristic (K x ) for at least one pressure (p x ) of the coolant ( 3 ) used for cooling the roll ( 1 ). 
 
     
     
       7. The method according to  claim 3  comprising the steps of:
 in case of measuring the pressure, producing the pressure-distance characteristic (K x ) by association of the coolant pressure with the gap height (h) between the roll surface and the cooling shell ( 9 ,  11 ); and 
 in case of measuring the volume flow rate, producing the volume flow rate-distance characteristic (K x ) by association of the volume flow rate with the gap height (h) between the roll surface and the cooling shell ( 9 ,  11 ). 
 
     
     
       8. The method according to  claim 1 , comprising the step of injecting the coolant from the nozzle ( 3 ) essentially parallel to a circumferential direction (U) of the roll tangentionally to the roll ( 1 ). 
     
     
       9. The method according to  claim 1 , wherein a flow direction of the coolant in the gap ( 7 ) is opposite a rotational direction of the roll ( 1 ). 
     
     
       10. The method according to  claim 9 , comprising the step of, with reference to the flow direction of the coolant ( 3 ) in gap ( 7 ), arranging a stripper ( 17 ) for stripping the coolant ( 3 ) from the roll surface at a remote end of the cooling shell ( 9 ,  11 ) so that only a small amount of coolant ( 3 ) reaches the metal strip ( 15 ). 
     
     
       11. The method according to  claim 1 , wherein the cooling shell ( 9 ,  11 ) is adjusted on the roll surface by one of tilting the cooling shell ( 9 ,  11 ) and by a translational movement of the cooling shell ( 9 ,  11 ). 
     
     
       12. A device ( 10 ) for cooling a work roll, comprising a cooling shell ( 9 ,  1 ) mountable on the roll ( 1 ), having a shape substantially complementary to a region of a roll surface, and extending at least over a portion of an axial width of the roll and at least over a portion of a circumference (U) of the roll ( 1 );
 a nozzle ( 5 ) for feeding coolant in a gap ( 7 ) between the cooling shell ( 9 ,  11 ) and the roll ( 1 ); and one of 
 a pressure sensor ( 13 ) for measuring pressure of a coolant in a region of the nozzle ( 5 ) and a device for setting a gap height (h) between the cooling shell ( 9 ,  11 ) and the roll ( 1 ) dependent on the coolant pressure (p act ) measured by the pressure sensor ( 13 ), and 
 a volume flow meter ( 13 ) for measuring a coolant volume flow rate in a region of the nozzle ( 5 ) and a device for setting a gap height (h) between the cooling shell ( 9 ,  11 ) and the roll ( 1 ) dependent on the volume flow rate (V act ) measured by the volume flow meter ( 13 ). 
 
     
     
       13. The device ( 10 ) according to  claim 12 , wherein the cooling shell ( 9 ,  11 ), viewed in a circumferential direction (U) of the roll ( 1 ), is formed of at least two parts, and both parts ( 9 ,  11 ) of the cooling shell ( 9 ,  11 ) pivot relative to each other about an axis (A) extending parallel to an axial direction of the roll ( 1 ). 
     
     
       14. A rolling device ( 100 ), comprising
 a roll ( 1 ) for rolling a metal strip ( 15 ); and 
 a device ( 10 ) for cooling the roll ( 1 ) wherein the device ( 10 ) comprises: 
 a cooling shell ( 9 ,  1 ) mountable on the roll ( 1 ), having a shape substantially complementary to a region of a roll surface, and extending at least over a portion of an axial width of the roll and at least over a portion of a circumference (U) of the roll ( 1 ); 
 a nozzle ( 5 ) for feeding coolant in a gap ( 7 ) between the cooling shell ( 9 ,  11 ) and the roll ( 1 ); and one of: 
 a pressure sensor ( 13 ) for measuring pressure of a coolant in a region of the nozzle ( 5 ) and a device for setting a gap height (h) between the cooling shell ( 9 ,  11 ) and the roll ( 1 ) dependent on the coolant pressure (p act ) measured by the pressure sensor ( 13 ), and 
 a volume flow meter ( 13 ) for measuring a coolant volume flow rate in a region of the nozzle ( 5 ), and a device for setting a gap height (h) between the cooling shell ( 9 ,  11 ) and the roll ( 1 ) dependent on the volume flow rate (V act ) measured by the volume flow meter ( 13 ).